nonolingo is an app for Mac that helps Vietnamese people write English naturally at work, right in the box you are typing.

Problem: many people at work write grammatically correct English but their sentences still "sound like translations," so every message to a boss or foreign client has to be read 3 or 4 times, or copied into ChatGPT, Google Translate, and pasted back.

Main features:

• Typing in any box (Slack, Gmail, Teams, Telegram, Zalo, WhatsApp, browser), nonolingo displays 2 lines right below: one correcting your message while keeping your meaning, and one rewriting it naturally like a native speaker. Press Tab to accept, Esc to skip. The app never sends on your behalf.
• Type in Vietnamese, receive back natural English.
• Highlight another person's message to get reply suggestions, or press T to translate it along with their tone and true meaning.

Who should use it: office workers, freelancers, developers, designers, product managers, marketers working with foreign clients or teams, sending English messages daily.

How to get started: download the free DMG file from nonolingo.com, drag it into Applications, then open it, granting Accessibility permission once. Requires macOS 14 or later, works on both Apple silicon and Intel. 7 days of full features without registration or credit card, and then still free each day. Pro package is a one-time payment (49,000 VND/30 days), not auto-renewed.

Difference: not a course, doesn’t require you to switch tabs. The correction maintains your voice instead of rewriting into a template, and understands the context of the conversation to match the tone.